NullPointException in RecyclerView

Question

I try to download list from server in AsyncTask and put it into recyclerView. However, I still get NullPointException on RecyclerView and have no idea why. I set LayoutManager a

Answer 1

Change Your AsyncTask Like This

                        public class GetUsersAsyncTask extends AsyncTask> {


                     public Context mContext;
                     private ChatMainFragment mFragment;
                     private RecyclerView mUserRecyclerView;

                     public GetUsersAsyncTask(ChatMainFragment fragment,RecyclerView mRListView) {
                         this.mFragment = fragment;
                         this.mUserRecyclerView=mRListView;
                     }


                     @Override
                     protected List doInBackground(String... params) {
                         List userList = new ArrayList<>();
                         try {
                             userList  = ServerConnector.getInstance(mContext).getChatUserList();
                          /*requestEnds(userList);*/
                         } catch (ServerConnectorException e) {
                             e.printStackTrace();
                         }

                         return userList;
                     }

                     @Override
                     protected void onPostExecute(List chatUserListItems) {
                         Log.e(TAG, "onPostExecute: ");
                         userList = chatUserListItems ;
                         ChatMainAdapter adapter = new ChatMainAdapter(getActivity().getApplicationContext(), userList);
                        mUserRecyclerView.setAdapter(adapter);
                        mUserRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity().getApplicationContext()));
                         adapter.notifyDataSetChanged();


                     }
                     }

and when you initiate your async class in onCreateView initiate it like this

 mUserListView = (RecyclerView)view.findViewById(R.id.user_list);
GetUsersAsyncTask task = new GetUsersAsyncTask(this,mUserListView);

Just replace the code and it should work as expected .. Hope this helps